<!DOCTYPE html>
<html>

<head lang="en">
    <meta charset="UTF-8">
    <title>使用document对象操作页面</title>
    <style type="text/css">
        body,
        input,
        div,
        p,
        {
        margin: 0;
        padding: 0;
        }

        body {
            font-size: 14px;
            font-family: "微软雅黑";
            line-height: 25px;
        }

        .content {
            width: 650px;
            margin: 0 auto;
        }

        .content img {
            float: left;
            width: 150px;
        }

        .r {
            float: left;
            width: 650px;
        }

        input[name="changeBook"] {
            width: 100px;
            height: 28px;
            line-height: 28px;
            text-align: center;
            font-size: 14px;
            font-family: "微软雅黑";
            margin: 10px 0 10px 0;
        }

        input[name="season"] {
            width: 100px;
            text-align: center;
        }
    </style>
</head>

<body>



    <div class="content">

        <div class="r">
            <div id="book">大数据技术最靓的仔</div>
            <input name="changeBook" value="换换名称" type="button"/><br>
            本学期课程：
            <input name="season" type="text" value="大数据呈现技术" />
            <input name="season" type="text" value="智能推荐技术与应用" />
            <input name="season" type="text" value="数据统计分析" />
            <input name="season" type="text" value="大学语文" /><br><br>
            <input name="b2" type="button" value="获取input内容" />
            <input name="b3" type="button" value="获取课程名称" />
            <input name="b4" type="button" value="清空页面内容" />
            <input name="b4" type="button" value="刷新整个页面" /><br><br>
            <input name="b4" type="button" value="弹出你真棒提示框，用户点击确定，在页面中写good,用户点击取消关闭整个窗口" />

        </div>
    </div>
    <script type="text/javascript">
        let a1 = document.getElementById().innerHTML="";
        let a2 = document.getElementsByTagName("");
        let

    </script>
</body>

</html>